Let's make the testing a bit more structured and useful. So please put all your Atari 2600 games, controller etc. related test results in here. If possible, verify your results with original consoles.
First, there are numerous games (especially homebrews) which are known to not work (yet). In brackets you find the bankswitching type name of Stella.
Pitfall II (DPC)
Activision (FE) (most likely): Decathlon, Space Shuttle, Robot Tank - Note: there exist cart versions (e.